Can we just stop talking about Hillary Clinton’s health now?

The reference, in case you missed it, is to an episode of coughing that struck Clinton at a rally in Ohio on Labor Day. (You can watch it here.) Drudge also linked to lots — and lots — of stories about the coughing.

This is not new. Led by Drudge, there have been questions circulating in the conservative media — and among Trump surrogates like Rudy Giuliani — that "something" is wrong with Clinton for months. Much of that speculation ties back to an episode in late 2012 in which Clinton caught a stomach virus, fell, suffered a concussion and was then hospitalized due to a blood clot. A certain sector of conservatives were convinced that more was going on with her health than ever became public and that this was yet another example of the Clintons hiding things from the public.

"Diagnoses" have run everywhere from a severe thyroid problem to traumatic brain injury to dysphasia. (That last one comes courtesy of Trump national spokeswoman Katrina Pierson, who, in case you were wondering, is not a doctor.)

And, of course, Trump sounded off on the whole thing Tuesday via Twitter.

So, to believe that something is seriously wrong with Clinton, you have to a) assume her doctor lied and b) that her coughing, which often happens when someone catches a cold or spends a lot of time speaking publicly, is a symptom of her deeper, hidden illness.

That seems, um, unlikely to me? Beyond the Clinton conspiracy theorists who believe she had something to do with Vince Foster's death and that she was secretly responsible for everything from Y2K to the SpaceX explosion last week, it's hard to plausibly insist, based on the available data, that Clinton is ill. There's the doctor's note, plus she keeps a very rigorous schedule for a 68-year-old — traveling all over the country to raise money and campaign. (For the past month, she's done a lot more raising money than campaigning.)

The extent of the "evidence" of Clinton's illness beyond the telltale cough is this reaction when surprised by a question from a reporter.

Then there is the fact that Trump himself — age 70! — has not exactly been forthcoming with the details of his own health. This is the letter his doctor released last year:

Compare that letter to the one from Clinton's doctor. One reads like a doctor wrote it. The other reads like Trump wrote it. Here's what Trump's doctor has said of the letter: "His health is excellent, especially his mental health. He thinks he's the best, which works out just fine." Er, okay!

The simple fact is that there is zero evidence that anything is seriously wrong with Clinton. If suffering an occasional coughing fit is evidence of a major health problem, then 75 percent of the country must have that mystery illness. And I am one of them.

What Trump cannot — or, at least, should not — do is continue to engage with these wacky theories that emerge out of the fever swamps on the very fringe of the conservative movement. Every single person who believes in the Clinton health conspiracy is already for Trump. What he needs to do is find ways to reach voters who have doubts about him but may carry even graver doubts about Clinton's ability to do the job in an honest and transparent way.

Clinton's botched handling of her private email server, the questions raised by the Clinton Foundation's foreign donors — these are ripe issues for Trump to make a case against Clinton. Every second he or his surrogates spend talking about Clinton's health is a lost moment for his campaign. And with 63 days left until the election, he simply can't afford that.